As the world moves relentlessly toward a cashless society, the venerable credit card has become a staple. So, too, in the corporate arena, where secret modes or methods are closely guarded and industrial espionage is seemingly on the rise, the ability to identify authorized personnel and distinguish them from interlopers has become an art form.
The foregoing examples are but two among a myriad of circumstances which call for the implementation of a system of secure identification by means of cards and badges. Drivers licenses, which are no longer simply evidence of payment of a fee, but have become a primary means of personal identification, are yet another category of use for secure instruments. The credit card issuers seem to be in competition to create the most decorative, yet secure instruments, and consumers seem to be attracted to issuers who provide more than just low introductory interest.
The security instrument industry seems to have taken on a life of its own and considerable research is being conducted into ways of producing an aesthetically pleasing identification card, or badge, which is incapable of being counterfeited and will destruct upon attempted alteration. The counterfeiting of identification documents involving as it does the alteration, fabrication, issuance and ultimately, use of such cards by persons not authorized to do so presents continual, and multiple security problems for legitimate issuers.
Perhaps the most effective, yet impractical, way to prevent counterfeiting would involve strict control over the possession of the materials and equipment involved in the fabrication of identification documents. For example, too many of the materials involved are commercially available and used in other, less sensitive, applications. To date, the more popular response to the counterfeiting problem involves the integration of several verification features to evidence authenticity. The best known of these “verification features” involve signatures such as the signature of the one authorized to issue the document, or the signature of the bearer. Other popular verification features have involved the use of watermarks, fluorescent materials, validation patterns or markings and polarizing stripes. These verification features and perhaps others, are integrated in various ways and may provide visual verification, or in some instances, invisible evidence of authenticity, in the finished card. If invisible, of course, authenticity is verifiable by viewing the instrument under conditions that render the invisible feature, visible.
The present invention is operative within this broad field, to teach a novel printing process using multiple colors to provide an interlocking design which is capable of producing an optically variable visual image, resulting in an instrument with enhanced security.